Here it is, an Ewave type center channel, dubbed "Malcolm". It uses a SEOS12 and (currently) one of Erich's "less good" clone drivers.

Almost done, just a little tweak needed on the crossover to smooth the curves a little more. Weather was good tonight and I had a little time to set up outside and take some pattern measurements. When I get some more time and energy, I'll work up a schematic and parts list and post it all as a build article on Erich's forum (if he ever opens it up, that is). Maybe he'll even do kits on it.

Woofers are 4x DS-115-8, cleverly (or so I think) arranged as a shaded horizontal line source. Near crossover, the middle pair plays dominantly to match the SEOS12 pattern, with the outer pair cutting in a few hundred Hz lower and continuing directivity like a 20" driver. The effect is rather good constant horizontal directivity down to about 500Hz, in a box only 12" high and 21" wide. 8" deep. The speaker cabinet looks a lot better than it appears in the camera photo (the flash does funny things inside the waveguide contours). The crossover mess on top, though, is every bit as ugly as it looks here -- needs to be put on a board and mounted inside.

The box is ported, tuned to 60Hz and has an F3 of about 57Hz when mounted against a wall (above or below an LCD monitor is the intention).

Here are the Horizontal curves, unsmoothed. 0 to 60degress in 7.5 degree steps-
Pretty good, huh? Check it out in the usual 1/6th Octave smoothing (0 to 90deg):

These are some color polar plots of the horizontal performance (map and cylinder formats):

In the vertical, the waveguide can only control directivity down to about 3kHz or so and the woofers (being only 4"ers) don't control it at all. But the very close 5.5" CTC keeps the curves smooth and useful so what does go vertically off axis is at least well-behaved. Vertical Upwards, 0 to 60, unsmoothed:\\
Vertical Downwards:

And here's the high-tech measuring "lab", including speaker precariously balanced on a ladder with a sheet of MDF clamped below to try to simulate an LCD screen. The whole arrangement is about a foot from the door behind it, so bass wasn't as good as it should be.

woofers are in series parallel, with the outer 2 being in parallel and the inner 2 in parallel. The outer 2 have a big capacitor shunting them, so at higher freqs there is more current into the centers, but only those are playing. At low freqs, less current but more drivers, so overall response is about flat.

so around 88dB efficient or did you throw some out to put in some baffle step?

While *I* think it looks cool, no way that is allowed in my house without a grill covering up that driver/waveguide arrangement... the aesthetic wouldn't fly at all. so hopefully any flatpack CNC cabinets will make the baffle a bit bigger for traditional looking grills or do something to allow low profile inset grills ala Harbeth.

should be around 88 to 90 dB, no baffle step (intended to be adjacent to tv screen and back up against wall). Sounds really good like that, though it sounds pretty anemic if out in midroom sitting on a barstool. It wants to operatw half space.

Ditto here about the grill. I'll be installing some magnets and make a grillu frame to make it more acceptable to the wife.

Sure, send the woof, I can work something up (probably will just model and not build, but PCD is pretty durn accuirate.

woofers are in series parallel, with the outer 2 being in parallel and the inner 2 in parallel. The outer 2 have a big capacitor shunting them, so at higher freqs there is more current into the centers, but only those are playing. At low freqs, less current but more drivers, so overall response is about flat.

Things should hopefully slow down for me in about a week. Once the first couple rounds of mowing are done, and the guys settle into some type of routine, it will be better. Right now it's sun up to sun down.

Then the mulching starts back up. But I'm going to back out of a good chunk of that and spend more time on the audio projects because I enjoy it more. I'm almost tempted to shut down the ordering on the site to get caught up and get the new stuff listed.

There's a very good chance that I'll have to hire a part timer to help package everything up that is coming soon. I can keep up with about 5 kits, some group buys, and these SEOS projects, but what's coming is going to hit almost all at the same time and we're looking at 20+ designs. My desk literally has over 20 designs piled on it right now that are in the works.

It would not be fair to let people wait longer than needed for this stuff, so I'm going to figure something out. I have to box up about 7 Anarchy flat packs that people ordered about 4-5 days ago. No doubt guys following this project understand that I'm trying to help out here, but with the site I no longer know who's actually ordering the stuff and they might just think I'm a huge slacker.

Quick heads up: The pallet of waveguides from Poland has shipped, but I haven't had time to contact those people to let them know their stuff is on it's way. I'll get a list of all the poured products available for the next pallet.

Funny Note: I had a lady friend stop over to my house this week. I haven't seen her for quite a while. She's a friend I've had for about 20 years and I don't mind what my house looks when she ever comes over. The first words out of her mouth:

"What the hell is going on here?" Obviously joking a bit.

I should take pictures before the massive spring audio clean up at E's house!

Bwaslo, that speaker looks great. The response looks really good too. You know I'll be getting a flat pack going for it!

Also forgot to mention that all the compression driver stuff is pretty much done and being shipped to one location before getting sent here. Waiting on one last manufacturer to finish up something else, then it will all get shipped at the same time.

Any plans for a higher efficiency version, say, with three Eminence Alpha 6's or something like that?

Hi Noah,

I don't think that would be worth it. The initial lone 6"er playing would be a poor directivity match for the SEOS12. The Fs is too high to get down to an 80Hz crossover without operating in the port region (complicating subwoofer alignment). The box would get 2" taller, too, which is a cosmetic problem for me at least.

Erich has been pushing for a SEOS12 over a pair of 6" but the baffle shape would be nearly square, pretty ugly. Maybe for a built-in or make it real wide with some ports. If I was going into that, I'd probably use the NS6 buyouts (the light weight would be nice for mounting over an LCD, too -- I haven't yet figured out how I'm gonna prop Malcolm over the screen here).

Maybe 4x NS6, that would get sensitivity up toward 97dB. Erich, wanna build a box for that?

Just out of curiosity bwaslo, could that center channel be used as a LCR setup?

Absolutely. There are definitely some advantages to a design like this. You will get horizontal directivity control lower than most other designs along with no vertical null issues.

Bwaslo, I thought I posted shortly after you showed your small woofer design but I guess I didn't. Anyway, awesome job. I've been interested in a design like this for some time, but I just haven't had the chance to implement it. What I really want to try is something like a SEOS-15 or 12 with 8 Dayton RS150T's crossed around 900-1000hz. They could be done in either a MWM or WMM setup. Of course, that wouldn't be too cheap, but the sensitivity would be great, distortion would be super low and cone breakup would be multiple octaves north of the passband.

Bwaslo:
Can you comment on what you didn't do with this HLA of small woofers and why. If it controls directivity down to 500 hz or so, why not use a 15" or 18" seos with the new BA CD and a lower crossover?
Since CtoC is so good, why not go MTM and get the vertical under better control?

Absolutely. There are definitely some advantages to a design like this. You will get horizontal directivity control lower than most other designs along with no vertical null issues.

Bwaslo, I thought I posted shortly after you showed your small woofer design but I guess I didn't. Anyway, awesome job. I've been interested in a design like this for some time, but I just haven't had the chance to implement it. What I really want to try is something like a SEOS-15 or 12 with 8 Dayton RS150T's crossed around 900-1000hz. They could be done in either a MWM or WMM setup. Of course, that wouldn't be too cheap, but the sensitivity would be great, distortion would be super low and cone breakup would be multiple octaves north of the passband.

I might be interested in that combo too. Doesn't seem outrageously expensive to me. It would give me something to do while waiting for my TD-15M's.

Here it is, an Ewave type center channel, dubbed "Malcolm". It uses a SEOS12 and (currently) one of Erich's "less good" clone drivers.

Almost done, just a little tweak needed on the crossover to smooth the curves a little more. Weather was good tonight and I had a little time to set up outside and take some pattern measurements. When I get some more time and energy, I'll work up a schematic and parts list and post it all as a build article on Erich's forum (if he ever opens it up, that is). Maybe he'll even do kits on it.

Woofers are 4x DS-115-8, cleverly (or so I think) arranged as a shaded horizontal line source. Near crossover, the middle pair plays dominantly to match the SEOS12 pattern, with the outer pair cutting in a few hundred Hz lower and continuing directivity like a 20" driver. The effect is rather good constant horizontal directivity down to about 500Hz, in a box only 12" high and 21" wide. 8" deep. The speaker cabinet looks a lot better than it appears in the camera photo (the flash does funny things inside the waveguide contours). The crossover mess on top, though, is every bit as ugly as it looks here -- needs to be put on a board and mounted inside.

The box is ported, tuned to 60Hz and has an F3 of about 57Hz when mounted against a wall (above or below an LCD monitor is the intention).

Here are the Horizontal curves, unsmoothed. 0 to 60degress in 7.5 degree steps-

Pretty good, huh? Check it out in the usual 1/6th Octave smoothing (0 to 90deg):

These are some color polar plots of the horizontal performance (map and cylinder formats):

In the vertical, the waveguide can only control directivity down to about 3kHz or so and the woofers (being only 4"ers) don't control it at all. But the very close 5.5" CTC keeps the curves smooth and useful so what does go vertically off axis is at least well-behaved. Vertical Upwards, 0 to 60, unsmoothed:
\\
Vertical Downwards:

And here's the high-tech measuring "lab", including speaker precariously balanced on a ladder with a sheet of MDF clamped below to try to simulate an LCD screen. The whole arrangement is about a foot from the door behind it, so bass wasn't as good as it should be.

Wow, I really like that form factor for LCR. Nice work, and thank you for doing all of this and posting it.

Bwaslo:
Can you comment on what you didn't do with this HLA of small woofers and why. If it controls directivity down to 500 hz or so, why not use a 15" or 18" seos with the new BA CD and a lower crossover?
Since CtoC is so good, why not go MTM and get the vertical under better control?

Thanks.
Jack

Hi Jack,

The SEOS12 was used because (1) it will be cheap since it is in plastic, (2) I was trying to keep height low as it is meant to be a middle channel above the TV monitor. The directivity down to about 1kHz is done by the waveguide, below that is done by the HLA. Using the term HLA loosely, here, as there are only 4 drivers in it.

An MTM would only add directivity in a small freq range down around crossover, below where the tweeter has already gone omnidirectional -- there would be a big bump off-axis from about 1kHz to 3kHz. Better to just have it act like a roll-off at 3kHz instead of a narrow freq range of pattern control. I also think an MTM with a waveguide is a bad idea in general since the CTC is then the distance between the M's below the frequency where the waveguide output goes away. Unless the waveguide is very, very short, and then it has no vertical pattern control. Or unless it is a Danley Unity/Synergy setup.

These also look like they'd be good candidates for side channels mounted high on the wall angling down towards the sitting position.

Actually, that would probably work really well for LR, too, if they could be mounted up against the ceiling, woofers at the top of the baffle near the ceiling to avoid reflection (ground-plane style), and of course toed in to cross ahead of the center seat. Not living room WAF style, of course, but it could be a sell for dedicated home theaters.

Edit: Now you got me thinking. First, speakers hanging from the ceiling might be better done with neo type woofers (NS6 buyouts come to mind again) to cut the weight down. The Malcolm using DS woofers is currently a box-o-magnets with all those big ferrite woofers.

Second, probably the long bottom side of the box (will be top side against the ceiling, when mounted woofers-above) could be sloped to move the baffle edge closer to the ceiling for that kind of installation.

Erich is better at cutting wood than I am, maybe when his day business settles down a little for the season I can talk him into making boxes like that to try. I need to finish up the DeltaLite 2512/Delta 12A/Designer 12 SEOS12 Ewave designs before getting sidetracked onto this. Or maybe someone else wants to take on the "Reese" ceiling mount speaker design?

Actually, that would probably work really well for LR, too, if they could be mounted up against the ceiling, woofers at the top of the baffle near the ceiling to avoid reflection (ground-plane style), and of course toed in to cross ahead of the center seat. Not living room WAF style, of course, but it could be a sell for dedicated home theaters.

Edit: Now you got me thinking. First, speakers hanging from the ceiling might be better done with neo type woofers (NS6 buyouts come to mind again) to cut the weight down. The Malcolm using DS woofers is currently a box-o-magnets with all those big ferrite woofers.

Second, probably the long bottom side of the box (will be top side against the ceiling, when mounted woofers-above) could be sloped to move the baffle edge closer to the ceiling for that kind of installation.

Erich is better at cutting wood than I am, maybe when his day business settles down a little for the season I can talk him into making boxes like that to try. I need to finish up the DeltaLite 2512/Delta 12A/Designer 12 SEOS12 Ewave designs before getting sidetracked onto this. Or maybe someone else wants to take on the "Reese" ceiling mount speaker design?

The SEOS12 was used because (1) it will be cheap since it is in plastic, (2) I was trying to keep height low as it is meant to be a middle channel above the TV monitor. The directivity down to about 1kHz is done by the waveguide, below that is done by the HLA. Using the term HLA loosely, here, as there are only 4 drivers in it.

An MTM would only add directivity in a small freq range down around crossover, below where the tweeter has already gone omnidirectional -- there would be a big bump off-axis from about 1kHz to 3kHz. Better to just have it act like a roll-off at 3kHz instead of a narrow freq range of pattern control. I also think an MTM with a waveguide is a bad idea in general since the CTC is then the distance between the M's below the frequency where the waveguide output goes away. Unless the waveguide is very, very short, and then it has no vertical pattern control. Or unless it is a Danley Unity/Synergy setup.

Good points on the MTM.

I think two rows of 4 NS6's below a SEOS-12/15 crossed around 1000-1200 would be hard to beat. Shading on the outer pairs would be good. Sensitivity would be pretty good with 8 91db drivers. I'd love to compare that to a SEOS over a TD15M.

For an MTM, I've thought about a JBL 2384 30x15" horn that holds vertical pattern so-so down to around 600hz with 5 6" woofers (the NS6 looks good) on top and bottom. With a 600hz cross that puts the woofers about 1 wavelength apart. Of course, this would be an approximately 32" x 32" speaker which is a bizzarre size. It would be great for a baffle wall. It would also work well with all of the woofers below.

The funny thing is that I would pair my $1000+ 2452H-SLs with an $80 array of woofers. I'm resisting the temptation to buy a truckload of the NS6's. These would work well in SEOS-6 MTs too.